1. Field of the Invention
The present invention relates to the reading of fingerprints, and more particularly concerns methods and apparatus for viewing a finger and providing a body of output data that accurately and precisely defines a fingerprint.
2. Description of Related Art
Fingerprint identification is becoming increasingly automated, and as advantages of automatic fingerprint identification systems become more apparent through widespread use, automated fingerprint identification systems are becoming more common and more widely used. Many of such automated fingerprint identification systems input an electronic representation of an unknown fingerprint for use in selection of one or more matching prints from a massive body of stored electronic representations of many fingerprints. Yet, despite the extent and sophistication of automated fingerprint matching, fingerprints still are captured and recorded by old and conventional procedures utilizing ink, ink pad, and roller to provide an inked impression which is scanned to form a digital electronic representation for storage or comparison. These conventional procedures are inconvenient, slow, and, in many cases, inefficient. They frequently fail to record adequate definition of certain details, singularities and minutiae that are employed in fingerprint identification and matching processes.
Various types of optical systems have been suggested for automatically capturing and recording a print without use of card and ink, but these systems fail to provide a print record that will meet established criteria, such as specifications established by the Federal Bureau of Investigation. These criteria must be met for efficient and effective input to the automated print identification and matching equipment. Prior optical reading systems produce output images that are unacceptably distorted and lacking in satisfactory definition and resolution.
Certain of the specifications of the Federal Bureau of Investigation, for example, require a fingerprint image that is free of distortion and is defined by five hundred pixels per inch in both horizontal and vertical directions. Previously known optical fingerprint imaging apparatus, such as the fingerprint imaging apparatus of U.S. Pat. No. 4,537,484, to Fowler, et al., the recognition system of U.S. Pat. No. 5,109,427, to Yang, the optical fingerprint imaging device of Rachlin, shown in U.S. Pat. No. 4,925,300, or the copying systems of U.S. Pat. No. 4,568,178 to Rios, fail to provide fingerprint images that meet established criteria.
Accordingly, it is an object of the present invention to provide for optical reading of a fingerprint by methods and apparatus that minimize or avoid problems of the prior art.